The present invention relates to a display device, and more particularly to a display device which drives liquid crystal molecules by using a transverse electric field mode.
Transverse electric field modes which liquid crystal display devices have attract attention as liquid crystal modes with each of which a wide viewing angle, and a high contrast are realized. An aperture ratio and a transmittance are further improved in one of those liquid crystal modes, especially, a Fringe Field Switching (FFS) mode than in an In-Plane-Switching (IPS) mode.
FIG. 11 is a top plan view showing an example of a main portion of a liquid crystal display device having the FFS mode. As shown in the figure, in the liquid crystal display device having the FFS mode, a plurality of scanning lines 203 and a plurality of signal lines 205 are wired in a matrix on a substrate 201 on a drive side. Also, pixel electrodes 209 are provided in intersection portions in which the plurality of scanning lines 203 and the plurality of signal lines 205 intersect with each other, respectively. Each of the pixel electrodes 209 is formed in sinking comb-like shape in which a plurality of electrode portions 209a extend along each of the signal lines 205 (or each of the scanning lines 203) by performing the patterning.
In addition, although an illustration is omitted here, a common electrode is provided in a state of being insulated from the pixel electrodes 209 through an insulating film below the pixel electrodes 209 on the substrate 201. This common electrode is provided at the same level as that of each of the scanning lines 203, or in an upper layer with respect to the scanning lines 203 and the signal lines 205. Thus, this common electrode is provided over the entire surface within at least a pixel “a”.
It is desirable for further improving the view angle characteristics in the liquid crystal display device which has the FFS mode and which is structured in the manner described above, it is advantageous to adopt a multi-domain structure in which the liquid crystal molecules “m” are dividedly aligned. In this case, as shown in FIG. 11, each of the electrode portions 209a is bent in different directions at a central portion along the extension direction, Thus, each of the pixels “a” is divided into two regions in which the corresponding ones of the electrode portions 209a extend in different directions. It is preferable to have mirror symmetry with a region boundary portion as a symmetric axis in terms of the optical characteristics. As a result, the liquid crystal molecules “m” are driven in different rotational direction in the two regions into which the pixel “a” is divided. Thus, the viewing angle characteristics (color shift) in a phase of halftone display or white display are improved. This technique, for example, is described in U.S. Pat. No. 6,809,789.